Automated pool cleaners for mechanical cleaning of swimming pool water have been known for many years. Some of the early patents include U.S. Pat. No. 3,278,949 issued to Whitaker on Oct. 18, 1966; U.S. Pat. No. 3,433,237 issued to Gelinas on Mar. 18, 1969; and U.S. Pat. No. 3,665,525 issued to Howard on May 30, 1972.
U.S. Pat. No. 5,882,512 issued to Denkewicz et al. discloses an automatic pool cleaner comprising a removable chemical dispenser which carries solid chemicals such as silver-containing particles or other sanitizing solid pellets. The pool cleaner mechanically cleans the pool water while dispensing water-sanitizing chemical(s) by dissolving solid sanitizing chemical particles or pellets contained in the chemical dispenser inside the pool cleaner. The Denkewicz apparatus is mechanically complex as compared to the conventional pool cleaner thereby making it more expensive to manufacture, and likely to require maintenance and eventual repairs by technically trained personnel adding to the overall operating costs. Furthermore, the cost of operation includes the purchase of the dry chemicals which are consumed and must be replaced. A significant disadvantage of the Denkewicz apparatus is the safety hazard created when the machine is removed from the pool and highly concentrated chlorine-containing water drips onto the pool deck where it can be contacted by barefoot bathers.
The use of an electrochemical chlorine generator for sanitizing swimming pool water as the water passed through the main water filtration and circulation system of the pool has also been known for many years. These are commonly known as “in-line” chlorinators by those familiar with the art. Some early patents for electrolytic chlorinators for swimming pool water sanitation include U.S. Pat. No. 3,351,542 issued to Oldershaw, et al. on Nov. 7, 1967; U.S. Pat. No. 3,458,414 issued to Crane, et al. on Jul. 29, 1969; U.S. Pat. No. 3,669 issued to Kirkham, et al. on Jun. 13, 1972; and U.S. Pat. No. 4,724,059 issued to Collier on Feb. 9, 1988.
By way of background, a chlorine generator electrochemically produces biocidal chlorine to sanitize pool water through an electrolysis process. During the process, salt, i.e., sodium chloride, or NaCl, present in the water is consumed on the electrode and chlorine (Cl2) is generated and quickly dissolves in the water. Thereafter, a disproportionation reaction takes place to convert the dissolved chlorine to hypochlorous acid and hypochlorite ions, which are the active chemicals for the sanitation of pool water.
The term “chlorine” is used in the description and claims that follow to mean the biocidally active forms generated by the electrochemical reaction and the disproportionation reaction described above.
Electrochemical chlorine generators, also referred to as chlorinators, are currently available from a number of commercial sources for use in establishing and maintaining bactericidal levels of chlorine in swimming pools. These in-line electrochemical chlorine generators are installed in-line with the main pumping and filter system outside of the pool. These devices are relatively expensive to purchase and require the services of an experienced plumber and an electrician for their proper installation. In an automated control system, a probe is immersed in the pool water system at a representative location and the probe electronically transmits a signal to a remote poolside power supply and associated controller/processor which, in turn, controls the periodic operation of the chlorine generator apparatus.
The terms “controller” and “controller/processor” are used interchangeably in the description and claims that follow and are intended to include such devices that are programmed by the manufacturer or distributor of the pool cleaner and those in which the programs can be selected by a technician or the user in order to adapt the operation and functioning of the pool cleaner of the invention to the particular conditions of the pool in which the pool cleaner is used.
The use of these permanently installed electrochemical generator systems is typically limited to larger commercial and institutional pools where the convenience associated with the essentially continuously controlled introduction of chlorine into the pool outweighs the initial costs. These devices also eliminate the need for the purchase of chemicals and either the use of maintenance personnel or automated chemical injection systems.
The initial capital outlay for the purchase of the equipment, as well as the expenses associated with installation by plumbers and electricians generally discourage the use of electrochemical chlorine generators for the residential pool market. However, saltwater electrochemical chlorinators do produce a highly effective bactericidal sanitizer from a mild saltwater solution that pool users generally find less objectionable than chlorine-producing chemicals typically used in residential pools.
An alternative electrochemical apparatus is disclosed in U.S. Pat. No. 4,992,156 issued to Silveri on Feb. 12, 1991, where the cell is attached to a wall of the pool above a circulating water outlet, and the movement of salt water through the cell is effected by gas lift, which is possible when the cell is directly exposed to a very large volume of water and is positioned proximate a piped pool water circulation system outlet. The gas lift, in combination with the piped circulation of the water, helps to dissipate the water in and around the cell into the adjacent bulk of pool water.
A principal disadvantage of the Silveri devices is the requirement to operate the pools water circulation pump in order to assure distribution of the chlorine generated. A typical pump motor operates at 20 amps and a significant amount of electrical power is consumed in moving the large volume of water during its operation.
Safety hazards associated with the build-up of chlorine require that power to the chlorine generator be interrupted if the pump stops.
It is therefore an object of the present invention to provide an apparatus for generating and distributing biocidal or bactericidal chlorine in pools and a method of operation that is essentially self-contained and the use of which requires no installation services by a plumber and requires no separate or specialized electrical power connections for its operation.
Another object of this invention is to provide an apparatus and method of operation that will prolong the useful life of a pool cleaner that is equipped with an electrochemical chlorine generator that serves as the sole means for sanitizing the water in a pool and maintaining the bacterial count at an acceptable level.
It is yet another object of the invention to provide an operational method and an apparatus for providing the desired concentration of chlorine by an electrochemical generator that relies on conventional chlorine test methods used for residential pools, thereby avoiding the necessity of using expensive electronic probes and data processing and transmission control systems.
A further object of the invention is to provide an apparatus and method for utilizing an electrochemical chlorine generator that efficiently and effectively distributes the chlorine throughout the volume of water in the pool in order to provide a uniform concentration of the desired chlorine and thereby avoid the localized high concentration regions associated with the apparatus and methods of the prior art.
A further object of the invention is to provide an electrochemical chlorine generating cell that can be easily and safely accessed and replaced by the owner or user of the pool cleaner without enlisting the aid of a trained technician.
Another object of the invention is to provide an automated system utilizing an electrochemical chlorine generator mounted on a robotic pool cleaner, the operation of the generator being controlled by signals derived from a submerged sampling probe and transmitted either directly or indirectly via a relay receiver/transmitter to the processor/controller on-board the pool cleaner.
Another object of the invention is to provide a chlorine monitoring system mounted inside or attached to the pool cleaner. The monitoring system generates an electrical or photoelectron signal which is proportional to the chlorine concentration in the monitored pool water. The signal is used as a feedback to control the level of the chlorine generation of the electrochemical chlorinator. The signal can be either directly tied to the controller IC board or sent via a wireless transmission device.